July 25, 2025
Effort is intangible and subjective
Currently no objective measure of effort exists in the NFL
Idea: previous research has explored professional soccer players reaching theoretical max acceleration capacity1
Goals:
Improve estimation of individual acceleration-speed (A-S) profiles using statistical models
Assess how frequently players operate near or exceed their limits as a proxy for effort
Game, play, player data from Weeks 1-9: 136 games
Player tracking data: each observation is a frame in 10 fps
Pre-processing:
Filtered to running plays where a running back (RB) is the ball carrier
Trimmed each play to frames between handoff and end of play
Derived directional acceleration
Gives no credit to low speed points
Unrealistic theoretical max speeds - not comparable to soccer
Penalizes players for being athletic
Does not differentiate between acceleration and deceleration
Average frame-level effort for each player
\[ \Psi_i = \begin{cases} \frac{1}{1+d_i} & a_i\geq 0 \\ \frac{1}{2}\cdot\frac{1}{1+d_i} & a_i<0 \end{cases} \quad \implies \quad \text{Effort} = \frac{\sum_{i=1}^n \Psi}{n} \]
A-S-based effort alone does not explain performance
Another way to validate effort metrics?
Change the definition of effort? Incorporate game context?